Modified .455 HE followed me home

[Muley Gil]

Factory .45 Colt pressures are lower than .45 ACP.

Back in the mid '70s, I owned a 6 1/2" .455 MK II hand ejector that had been converted to .45 Colt. I loaded it with Keith SWCs over a charge of Unique. The ends of the bullets came right to the end of the cylinder. Looked mean as heck! It shot well, even with bullets sized to .452".

 

[awp101]

Yes they are but I still have it in my head I want to run both from this one. I'll keep mulling it over.

 

[awp101]

OK, I think I've finally decided to go .45 Colt only with this one due to a .45ACP revolver making it's way into the stable yesterday (a Ruger that y'all don't want to see anyway ).

Looking at The Book, a 1917 cylinder should work (1.55") if I can't find a suitable .455 cylinder but that's what my shaved .455 already measures.

There's a bit of endshake. Will the shims to correct it tighten the headspace? I've never shimmed a cylinder before so I don't know. The parts guy yesterday thought the headspace was excessive for the Colt but he just eyeballed it and didn't actually measure since the current cylinder has not been modified for the .45 Colt.

I feel like I'm missing something in my thought process. Am I, and what is it?

 

[DWalt]

As has been mentioned here numerous times, one way to convert to .45 Colt is to chamber in .45 Colt, but not all the way in. Just far enough to allow adequate headspace to allow cylinder rotation, with seating on the case mouth. That would be the only way to go if you indeed have a shaved .455 cylinder (and it seems that you do), and would therefore allow the use of both .45 Colt and clipped .45 ACP rounds. I suppose if I had such a .455, I would handload .45 ACP using lead bullets and minimum (starting) powder charges for it. I like the idea of multi-caliber handguns, but in this case I would probably shoot far more handloaded .45 ACP rounds than .45 Colt.

 

[awp101]

As has been mentioned here numerous times, one way to convert to .45 Colt is to chamber in .45 Colt, but not all the way in. Just far enough to allow adequate headspace to allow cylinder rotation, with seating on the case mouth.

That's the part that hasn't been registering, now I think I understand! I keep thinking run the reamer through so it headspaces on the rim which would actually create excess headspace in this case. What I should have been thinking is run it in until the headspace is correct and it will actually be seated on the case mouth. I take it this leaves a small amount of unsupported brass near the rim?

Some days I are slower than others...

 

[DWalt]

You got it. There is a slight amount of case protrusion from the cylinder face, but that's OK.

 

[pdcrig]

This sounds like a pretty cool project. Keep us posted.